1. Field of the Invention
The present invention relates to a microwave continuous heating apparatus in which a to-be-heated object continuously passes through a heating compartment, and microwave electric power is irradiated onto the to-be-heated object to heat the same in the heating compartment. More particularly, the present invention relates to a microwave continuous heating apparatus in which it is not necessary to irradiate microwave electric power intermittently when the to-be-heated object is transferred into or removed from the heating compartment, and microwave electric power is prevented from leaking and, additionally, the quality of the to-be-heated object is improved by uniformly irradiating microwave electric power onto the to-be-heated object.
2. Description of the Related Art
Conventionally, in a general microwave continuous heating apparatus, the to-be-heated object is transferred into the heating compartment through an entrance side opening provided in the heating compartment, and microwave electric power is irradiated onto the to-be-heated object in the heating compartment. After that, the to-be-heated object is removed from the heating compartment through an exit side opening provided in the heating compartment.
However, if such an apparatus is used, there is a problem in which microwaves leak toward outside of the heating compartment through the opening.
In view of the above situation, the object of the present invention is to provide a microwave continuous heating apparatus in which leakage of microwaves is reliably prevented so that a heating process is efficiently carried out by continuously irradiating microwave electric power.
To archive the above object, according to a first embodiment of the present invention, there is provided a microwave continuous heating apparatus provided with a heating compartment having openings at its front and rear portions; and a transfer device which carries a to-be-heated object held thereon through the heating compartment, whereby the object to be heated is irradiated with microwave electric power while passing through the heating compartment to heat the same, comprising microwave absorbing compartments connected to the front and the rear portions of the heating compartment so that the object to be heated can pass therethrough; and a plurality of reflecting plates of metal which are spaced from each other in a forward and backward direction and which are transferred by the transfer device, wherein the object to be heated is placed between two adjacent reflecting plates, and the reflecting plates are placed on the transfer device so that at least one reflecting plate is positioned in each microwave absorbing compartment, at least during irradiation of microwave electric power in the heating compartment.
In a microwave continuous heating apparatus having the above structure, a plurality of to-be-heated objects that should be processed are placed between two adjacent reflecting plates, respectively, and are successively transferred into the heating compartment and, then can be heated by microwave electric power while passing through the heating compartment.
The reflecting plate is placed on the transfer device so that at least one reflecting plate is positioned in a path of each of front and rear microwave absorbing compartment, at least during irradiation of microwave electric power in the heating compartment. Therefore, even if the size of the to-be-heated object is larger than the wavelength of the microwave electric power used in the heating compartment, microwave electric power is effectively reflected, absorbed and dispersed by the microwave absorbing compartment and the reflecting plate positioned in the absorbing compartment.
Therefore, it is not necessary to intermittently irradiate microwave electric power, and thus, the to-be-heated object can be efficiently heated by continuous irradiation of microwave electric power.
Even in conveyance of to-be-heated objects at the minimum pitches corresponding to the distance between the objects, microwave electric power can be prevented from leaking in the microwave absorbing compartment, and the to-be-heated objects can be certainly transferred. Also, as the microwave electric power can be continuously irradiated, the length of the heating compartment and the length of the microwave absorbing compartments provided at the front and rear portions of the heating compartment can be minimized, to thereby make the apparatus small, as a whole.
Especially, since an unnecessary space between the objects to be heated can be minimized, the number of objects to be heated that can be accommodated in the heating compartment can be increased. Thus, a heating efficiency by microwave electric power can be enhanced, and the cost for the heating process can be reduced.
According to a second embodiment of the present invention, in addition to the first embodiment, there is provided a microwave continuous heating apparatus, wherein the to-be-heated object and the reflecting plates are supplied onto the transfer device in the vicinity of an entrance of the microwave absorbing compartment provided at the front of the heating compartment, and are removed from the transfer device in the vicinity of an exit of the microwave absorbing compartment provided at the rear of the heating compartment.
In a microwave continuous heating apparatus according to the second embodiment, as a distance in which the to-be-heated object and the reflecting plate are transferred by the transfer device can be minimized, a load applied to the transfer device can be further reduced.
According to a third embodiment of the present invention, in addition to the second embodiment, there is provided a microwave continuous heating apparatus, wherein the reflecting plates are made integral with a jig on which the to-be-heated object can be placed at a front end or a rear end, or both the front and rear ends of the jig.
In a microwave continuous heating apparatus according to the third embodiment, as the reflecting plate is integral with the jig, when the to-be-heated object is placed on the jig, a space between the to-be-heated object and the jig can be easily maintained at a predetermined space, and the to-be-heated object along with the reflecting plate can be supplied onto or removed from the transfer device via the jig. Thus, the operation efficiency can be improved.
According to a fourth embodiment of the present invention, in addition to the third embodiment, there is provided a microwave continuous heating apparatus, wherein a plurality of vacant jigs having no object to be heated thereon are placed and transferred at the front and rear portions of the jig having the object to be heated thereon, respectively.
In a microwave continuous heating apparatus according to the fourth embodiment, the to-be-heated object placed on the jig integral with the reflecting plate is transferred, and at least one reflecting plate can be easily placed on a path of each of the front and rear microwave absorbing compartments, at least during irradiation of microwave electric power in the heating compartment, by effectively using the jig.
According to a fifth embodiment of the present invention, there is provided a microwave continuous heating apparatus provided with a heating compartment having openings at its front and rear portions; and a transfer device which carries a to-be-heated object held thereon through the heating compartment, whereby the object to be heated is irradiated with microwave electric power during passing through the heating compartment to heat the same, comprising microwave absorbing compartments connected to the front and the rear portions of the heating compartment so that the object to be heated can pass therethrough; shutters provided at the front and rear openings of the heating compartment; and a plurality of reflecting plates which are arranged in a line with the objects to be heated, in a transfer section between the vicinity of an entrance of the microwave absorbing compartment provided at the front of the heating compartment and the vicinity of an exit of the microwave absorbing compartment provided at the rear of the heating compartment, wherein the front and rear shutters are opened when the frontmost to-be-heated object or the reflecting plate of the line reaches the vicinity of the shutter, and are closed when the rearmost to-be-heated object or the reflecting plate of the line passes through the shutter.
In a microwave continuous heating apparatus according to the fifth embodiment, a plurality of reflecting plates, which are arranged in a line with the to-be-heated object, is transferred through a transfer section between the vicinity of an entrance of the microwave absorbing compartment provided at the front of the heating compartment and the vicinity of an exit of the microwave absorbing compartment provided at the rear of the heating compartment, and shutters provided at front and rear openings of the heating compartment is opened when the frontmost to-be-heated object or the reflecting plate of the line reaches the vicinity of the shutter, and are closed when the rearmost to-be-heated object or the reflecting plate of the line passes through the shutter. Therefore, when the shutters are closed, the shutters can prevent leakage of microwave electric power from the heating compartment.
On the other hand, when the shutter is opened, the reflecting plate is positioned in the path of the microwave absorbing compartment, so that microwave electric power can be effectively reflected, absorbed and dispersed by the microwave absorbing compartment and the reflecting plate positioned therein, even if the size of the to-be-heated object that passes through the front and rear openings of the heating compartment is larger than the wavelength of the microwave electric power used in the heating compartment.
Therefore, it is not necessary to intermittently irradiate microwave electric power and, thus, the to-be-heated object can be efficiently heated by continuous irradiation of microwave electric power.
Even in conveyance of to-be-heated objects at the minimum pitches corresponding to the distance between the objects, microwave electric power can be prevented from leaking, and the to-be-heated objects can be certainly transferred. Also, as the microwave electric power can be continuously irradiated, the length of the heating compartment and the length of the microwave absorbing compartments provided at the front and rear portions of the heating compartment can be minimized, to thereby make the apparatus small as a whole.
Since an unnecessary space between the objects to be heated can be minimized, the number of objects to be heated that can be accommodated in the heating compartment can be increased. Thus, a heating efficiency by microwave electric power can be enhanced, and the cost for the heating process can be reduced.
It is not necessary to transfer a number of vacant reflecting plates when a plurality of to-be-heated objects are transferred. Therefore, the number of reflecting plates that are necessary when the to-be-heated objects are heated can be minimized.
Therefore, a load applied to the transfer device can be reduced, and the efficiency of heating can be improved.
The to-be-heated object and the reflecting plate can be supplied onto the transfer device in the vicinity of the entrance of the microwave absorbing compartment provided at the front of the heating compartment, and can be removed from the transfer device in the vicinity of the exit of the microwave absorbing compartment provided at the rear of the heating compartment. Therefore, a distance in which the to-be-heated object and the reflecting plate are transferred by the transfer device can be minimized, and a load applied to the transfer device can be further reduced.
According to a sixth embodiment of the present invention, in addition to the fifth embodiment, there is provided a microwave continuous heating apparatus, wherein the reflecting plates are made integral with a jig on which the object to be heated can be placed, at a front end or a rear end, or both the front and rear ends of the jig.
In a microwave continuously heating apparatus according to the sixth embodiment, since the reflecting plate is integral with the jig, when the to-be-heated object is placed on the jig, a space between the to-be-heated object and the jig can be easily maintained at a predetermined space, and the to-be-heated object along with the reflecting plate can be supplied onto or removed from the transfer device via the jig. Thus, the operation efficiency can be improved.
According to a seventh embodiment of the present invention, in addition to the first or the fifth embodiment, there is provided a microwave continuous heating apparatus, wherein the transfer device has a circulating carriage, and the reflecting plates are spaced and placed on the entire periphery of the circulating carriage.
In a microwave continuously heating apparatus according to the seventh embodiment, as the reflecting plates that are spaced from each other are circulated along with the circulating carriage, an operation for supplying the reflecting plate onto or removing the same from the transfer device can be omitted, and the to-be-heated object can be easily transferred by only placing the to-be-heated object between two adjacent reflecting plates.
At least one reflecting plate can be easily positioned in each of both microwave absorbing compartments, at least during irradiation of microwave electric power in the heating compartment.
According to an eighth embodiment of the present invention, in addition to the first or the fifth embodiment, there is provided a microwave continuous heating apparatus, wherein the shape and size of the reflecting plates are such that they can pass through the microwave absorbing compartment with a slight gap, and the inner surface of the microwave absorbing compartment is covered by a microwave absorbing body.
In a microwave continuous heating apparatus according to the eighth embodiment, even if the size of the to-be-heated object is larger than one wavelength of the used microwave, almost all of the microwave electric power that leaks from the heating compartment to the microwave absorbing compartment can be reflected during movement of the reflecting plate within the microwave absorbing compartment.
Microwave electric power that passes through a small space between the reflecting plate and the microwave absorbing body can be effectively absorbed, attenuated and dispersed by the microwave absorbing body.
Therefore, the length of the microwave absorbing compartment can be minimized, so that the size of the apparatus can be entirely reduced.
According to a ninth embodiment of the present invention, in addition to the first and the fifth embodiment, there is provide a microwave continuous heating apparatus, wherein the reflecting plates bent in the form of xe2x80x9cLxe2x80x9d in cross section or is curved, in cross section, toward the object to be heated.
In a microwave continuous heating apparatus according to the ninth embodiment, as the reflecting plate is L-shaped or is curved in cross section, microwave electric power is prevented from leaking by the reflecting plate, and the reflected microwave electric power is acted on the to-be-heated object. This contributes to a uniform heating of the to-be-heated object.
According to a tenth embodiment of the present invention, in addition to the first and the fifth embodiment, there is provided a microwave continuous heating apparatus, wherein the reflecting plates are each comprised of a first planar reflecting plate and a second reflecting plate that is L-shaped or is curved in cross section toward the object to be heated.
In a microwave continuous heating apparatus according to the tenth embodiment, microwave electric power is prevented from leaking by the first planar reflecting plate, and microwave electric power is reflected toward the to-be-heated object by the second curved reflecting plate. This contributes to the uniform heating of the to-be-heated object.
According to a eleventh embodiment of the present invention, in addition to the first or the fifth embodiment, there is provided a microwave continuous heating apparatus, wherein ceramic bodies as the objects to be heated, are continuously heated.
The eleventh embodiment provides a microwave continuous heating apparatus used as a drying apparatus to dry a ceramic, for example, a ceramic honeycomb body.
The present invention may be more fully understood from the description of preferred embodiments of the invention set forth below, together with the accompanying drawings.